Power transmission



June 25, 1946. A. L, ELLIS POWER TRANSMISSION Filed July 25, 1935 ,5Sheets-Sheet l INVENTOR @Yen/un fuis H/S ATTORNEY. I

June 25, 1946. A, L ELUS. 2,402,742

PowER TRANSMISSION Filed July 2s, 1955 3 sheets-sheet :a

25 /4L /6 /7 ,.9 sgi /Z T//l/HLf/.LIS

4 m; HS ATTORNEY.

June 25, 1946.

A. L. ELLIS POWER TRANsMssIoN Filed July 23, 1955 5 Sheets-sheet 3INVENTOR HBrYrTHl/n Lf-Lus M or. M

Hhs ATTORNEY,

Patented June 25, 1946 lJN l 'lSED PATE N T v0F! m4023191POWERTRANSMISSION 'AnthurL Ellisy-Deep River,Y Conn., assignor to TheWaterbury yTool Company, Waterbury,

Conn., a ycorporation of Connecticut Application 'Jul'y 2)'3, 1935,Serial "-Nof'32g755 This invention relates, fgen-erally, to powertransmissions and the ninvention :has reference, more particularly, tola novelrfluidiorhydraulic pressure operated and controlledIdrivefsystem adapted to automatically l drive 1a .load :device throughVa predetermined acylcle :.'f foperaltion. Such a power transmissionfi's.adapted lfo'riuse With many' diierent load:devicestwithiwhifchiit -isdesirable to be able'to .control the @acceleration and deceleration,precisely "fori driving thei device with varying velocitythroughfapredetermined cycle of operation.

For example, the presen-tlinventionisiparticularly suitable for hoistsAor conveyorsfor transporting articles from 'one-pointto an'other. Ifthe larticles to be f transporte'dllare "of --aiiragile'l or delicatenature, such -"tha`;-t fclamage isli-kely I to occur if theyfare'subjectfedlto "-ja'rs ylar-1d1j`olts, 'it becomes Idesirable to"provide a -`"convey'or Idri-ve which will insure 'not fo'nly that theconveyor itself does not cause' any ia'rringlof fthe articles loaded'thereon but also'that the Lcorw'yo'r "may be loaded andunloadedbytheiattendantsftvithe out requiring ahigh Jdegree of'deiiterityftoinsure against damage occurring when placing articlesthereon and removing them 'therefromwhile maintaining a reasonablyn'highfspee'd "of transportation on the conveyor.

These and other considerationsniake'it'desirable to provide a conveyor:drive 'which may 'be controlled to operate, forle'xa'nplea chain typeconveyor, at varying 'speeds and vvith"\na1`^5`fing accelerationsand'decelerations under4 precise. and positive control. Thus,forexamvple,'in some conveyor installations it is desirableto operate theconveyor intermittently with a period ofvres'tffor loading at one endand unloadingat the `other end, and then upon the completion of loadingand unloading to move the conveyor through-the distance required tobring an article vintofvplace at the unloading station and an emptyflight -into place at the loading station. -It-is desirable to socontrol the conveyor drive asto make'thisvmovement start and stop withthe maxi-mura acceleration and deceleration, respectively, consistentwith the previously mentioned limitations re'- garding jarring of thearticles :on the conveyor.

Heretofore, chain type conveyors/or fh'oists have largely been driven byelectric motorsp'either directly or through reduction gearing, and inorder to obtain the Wide variationsin-speedlrequired to operate suchhoi'sts eiiicientlygitihas been necessary, even Wheneusing sa:D. C.supply, to employ a complicated l'andf'easily 'deranged 14`Claims. (Cl.198-3'7 system :of electric .'rheostats and l"control runits. It is Yfar.preferable to `use fanfAgCnsupply'with the result thaty itlhasbeen:exceedingly diilicult;A if notlimpossibl'ejto obtain ithedesiredgspeedlvariation ne'cessary for the ecient.operationlofrelec- `trie,..rnot'ordriven cham typehoi'sts'oWingtoth-e inherent nature of C. .motorsto/operaterfat constant or synchronousspec-d,` and :asia result,attempts have beeni made tooperate Tesine-"chain hoists 'continuously='at constant vs'pee'd, `'which is low lspeed 'of operatiombu-t lis"hard on fthe -'attendants since they 'mu'st''l'oad ard :unload thearticles While the conveyor or"hoi'st'visfmoving, Y 'and 'this must f'bedone' without undue oltinfgor being loaded :and y.removed .during theperiods Whenthe ehoist ,is stationary. -fAlternatively the second or'constant speedestep -in theeoperating 1 cycle maybeomittedwhenitislpossible tofuse the fullvm'ovement for acceleration andldeceleraltion.

#speed `power-source toi1 the-ihoistrlor conveyorflthe 'Another objectofthe-.present inventiontliesYf-in' atedcontrol means for determiningthef-periodsf j operation and the speeds of operation of the Waterburymotor or B-end that drives the hoist or conveyor, said control meansbeing responsive to such factors as the loading and unloading ofarticles, the closing of conveyor casing doors, etc., in addition to thepredetermined setting or adjustment of the output capacity of thetransmission pump or A-end.

A further object is to provide a novel hoist or conveyor drive systemcomprising a substantially constant speed motor, a variable speedtransmission driven by the motor and a hoist or conveyor driven by thetransmission at varying speeds and accelerations.

It is also an object to provide a control system for a variable speedtransmission operable to drive a load device through a predeterminedcycle of operations in response to conditions at the load device.

Still another object of the present invention is to provide a novelfluid pressure hoist drive system that is of rugged and of comparativelysimple construction, the same eliminating the use of troublesomevariable electrical resistances, change gears, etc., the said systembeing adapted for manual operation and control of the hoist drive whendesired, as upon failure of the supply current to the electric drivingmotor.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Fig. 1 is a schematic View in elevation, illus trating a portion of thenovel iluid pressure operated and controlled hoist drive of thisinvention employed for operating a hoist or conveyor of the chain type.

Fig. 2 is a schematic view in elevation, illustrating the remainingportion of the hoist drive of'Fg. l.

Fig. 3 is an enlarged sectional detail view of the means employed inFig. 1 for varying the output of the pump end of the variable speedtransmission.

Fig. '4 is a part sectional view taken along line 4-4 of Fig. 3, lookingin the direction of the arrows.

Fig. 5 is an enlarged fragmentary sectional view taken along line 5-5 ofFig. 2, looking in the direction of the arrows.

Fig. 6 is a fragmentary view showing a position of the cam mechanismduring the operation of the hoist.

Referring now to the drawings, the reference numeral I designates asubstantially Constant speed electric motor, such as a synchronous motorwhere an A. C. supply is used, the said motor having its rotor shaft 2connected in driving relation through a flexible coupling 3 to the mainshaft 4 of a iluid pump `5 of a Waterbury transmission. The constructionand operation of this type of transmission, including the fluid pump `5,is old and well known to those skilled in the art and hence would appearto require no detailed description, a brief description of the samebeing given in my Patent No. 1,868,697 of July 26, 1932.

Generally this type of transmission comprises a fluid pump, termed theA-end which pumps a suitable pressure motive fluid, hereinafter referredto merely as oil, to a fluid motor, termed the B- end. Either the A-endor the B-end, or both are constructed so that the displacement may bevaried relative to the displacement of the opposite end therebyproviding for the transmission of power at variable speed and torqueratios. In the form illustrated the A-end is provided with means forvarying its displacement by regulating the piston stroke while the B-endis of fixed displacement.

It is to be understood that any suitable, preferably constant speedmotive means may be used in lieu of motor I for driving the pump 5, forexample, a turbine or engine may be used, and this motive means may begeared down, if desired.

According to the preferred arrangement, the pump or A-end 5 delivers oilthrough pipe line 6 having a check valve 1 therein to the casing 8 of aby-pass valve 9 of the piston type. With the by-pass valve 9 in theposition shown in Fig. 2, oil from supply pipe line 6Iflows withincasing `8 to the return pipe line I0 leading to the casing I I of amanually operated interlock valve I2, also of the piston type. Withinterlock valve I2 in the position shown in Fig. 1, oil from casing IIflows through return pipe line I3 back to the pump or A-end 5.

By-pass valve 9 is biased to the position shown in Fig. 2 by the actionof a coil compression spring I4 contained within a hydraulic cylinder I5that is attached to one end of valve casing 8. Spring I4 .presses upon ahyraulic piston I6 reciprocable within cylinder I5 and having a pistonrod I1 extending through the head of cylinder I5 for fixed attachment tovalve I9, so that the pressure of spring I4 on piston I6 is transmittedthrough rod I1 to urge valve 9 into the position shown in Fig. 2. Undersuitable conditions, as Will further appear, control pressure fluid issupplied through pipe I8 to the space .between piston I6 and the head ofcylinder I5, thereby forcing piston I6 outwardly against the tension ofspring I4 into the dotted line position shown in Fig. 2, in Whichposition operating fluid or oil delivered by supply pipe line 6 flowswithin casing 8 to pipe line I9 and through this pipe line into thecasing 20 of a reversing valve 22 of the piston type.

With reversing valve 22 in the position shown in Fig. 2, pressureoperating fluid flows from casing 20 through pipe 23 into one port ofthe rotary hydraulic motor or B-end 24 of the Waterbury transmission,thereby driving the hydraulic motor 24, the oil leaving this motor byits other port and passing through pipe 42 to casing 22, from Which thisoil ows by Way of pipe 43 to valve casing 8 and thence by way of returnpipe line I0 back to pump 5. The main shaft 25 of this motor 24 is thuscaused to rotate in one direction, which motion is transmitted through aexible coupling 26 to a worm shaft 21. Shaft 21 extends into a reductiongear housing 29 and has a worm 28 fixed thereon that meshes with wormwheel 3U xed on a drive shaft 3 I, which drive shaft drives the drivingsprockets 32 of the hoist chains 33 through a suitable drivingconnection, not shown.

Thus, with operating pressure fluid supplied through pipe 23, the motor24 acts through reduction gearing 28, 30 and shaft 3I to rotatesprockets 32 in a counter-clockwise direction, as viewed in Fig. 2,thereby effecting the raising of articles 34 carried by the fights 35 ofchains 33.

Reversing valve 22 is adapted to be held or locked in the raisingposition illustrated `in Fig. 2 by means of a manual operating lever 36pivotally supported at 31 and connected by link 38 to the operating rod39 of valve 22. Lever 36 is shown as held or locked by the springpressed detent 4B engaging a notch in a segmental plate 4|-, the notchbeing desig'Iated'Onftl/lje'plate''l by the indicia. Rjsignifyingfraisirigy i. egph'e position of uetet 4t toeffeet the raising orme'-vation of articles fromfloorto fioo'rffl'ti. If detent 40 is releasedandlev'e'r' thrownto the left in Fig. 2, so thatjthis detententersriotch L,then'reversing valve 22'will have beenmov'ed to its dotted lineposition,'in which positionfp'ressure fluid supplied from .pipe i9entersmotor Z4 b'y way of pipe [i2 and leaves by Way of pipe '23,thereby rotating this motor in the reverse directin to cause thelowering of ancle's from floor 45 to noor'u.

The fluid pressure controlmean's for 'automaticallyeontrolling theoperation of the Waterbury transmission v'and hence 'the operationvofthe h`oist 2 I, comprises anauXlia-ry pump'having'its operating shaftcoupled toian extensioniof themain shaft li of the puinpor 'A-end 5. AuX- iliary pump 47 serves to draw oil or other'suitable `pressure fluidfrom 'the tank "or reservoir "#39 through pipe 50 and delivers this oilinto 'acon- 'trol'pipe line 5l. A relief Valve`52 connects with controlpipe line and the setting of thisfvalve determines the maximum fluidpressureobtaining in this pipe line 5I. Relief valve 52 dischargesthrough pipes 53, 54 and 5) back into reservoir A`re1ief valve 55 isincluded in pipe linefi 'and the setting of this valve determines thesubstantiallyconstant pressure with oil is delivered to a pipe 56branching from pipe linebi at a point between valve 55 and pumpe?? Aswill further appear, oil delivered through pipe 5% is adapted to passinto the casing 5'! o'fa'pilot control valve 58, and thence this oilpasses through o'ne of the two pipes 59 or '63, depending uponthe'position of valve '58, to the segmental casing 6i of a hydrauliccontrol means having a fan type impeller 62 therein that is iixed on thecontrol shaft 63 of the pump or A-end'5.

llmpeller E2 is actuated 'by or Aturned Within casing '6i by the oil orother pressure 'uid'deliveredby pipes 5 or Bil, thereby turning controlshaft 63 and determining the output of pump 5. Adjustable stop screws E5and G5 are threaded inwardly throughvoppositesides of casing 6| forlimiting the turning movement of impeller 62. Thus, screw 65 by limitingthe clockwise turning movement of impeller AE52 (see Figs. 1 and 3)serves to determine the maximum output of pump l5, whereas screw 66 bylimiting the counter-clockwise turning movement of impeller 52, servesto determine the minimum output or displacement of the pump 5, so thatthis pump will always deliver a certain amount of oil, thus maintaininga flow within the pipe line t. Pipes 59 and are illustrated as havingsuitable adjustable chokes 31 therein to control the rate of flow of oilto andl from the segmental casing Gi, thereby determining the rate atwhich impeller 62 is'movecL and hence the rate at which the output ofpump A5 changes, which in turn determines Athe rate of acceleration anddeceleration of the motor 2d and hoist 2l.

Oil from auxiliary pump 41 passing valve 5 5 ows within control pipeline 5I to the casing $8 of a -pilot reverse valve-69. Pilot reversevalve 69 serves to reverse the flow of control oil or fluid supplied toa series of pilot valves li), -l and 12 and is connected by a rod 'I3 tothe reversing valve 22 for actuation by the latter. Pilotvalve l0 ismovable within a casing 'id and isactuated by a rod YI5 connectedthrouglrlinlgagelfto,the hoist loading door TI. Pilot valve 'H ismovable vconnected to a trip lever Bi having an'upturne'd ifree"en dportion`8'l thatis positione'djwith'fthe heist 21 jStatipriel-ry,Veaijaeent aniram nightss 'adapted to "receivean'article'at-theloadingposinon; A- suitebieytensiep spring c2 tends'te-'heid the 'valve .1| in the fuii'iine position' ehvhinrig 2 in whichposition the vtrip-lever portion-58! proj ects somewhat above the"adjacent y'stationary ferie-in 'flieht 35. 'A 'nanfa 1 iever etaisrigidly-Se- Vc'uredto 4the trip lever-e9 for manual lo'p'eration'P1101-l valve 'i2 is" 'moves-1e within Le* eene-gian andis actuated farod V8,5 'connected to-'a v'trip lever '86 havingfa downturned free endVprtion lthat'is positioned, with'the hoist 2| -stati0n' ery, adjacent a@hamm-'eht 13e; at the 'top efthe threegconditions havebeen fulfilled,i. e., firstly,r

an article must be placediin thelower loading position, thereby'depressing lever en@ 4`rmrtibn i8 e;

and vactuating Atrip YleverSixto movef'vlalve "il from its full line toits dotted"line' po`sitin; secondly,

the loading door 11 Tmuet be closed, thereby' operating linkage 76 tomovevalve. l0 froml its fullfl'rle to its ',dtt'ed'lri'e position; andthirdly, any article in`the upper delivery Yposition must have beenremoved so that pilot valve 'l2 isin the full line position Vshown inFig. 2. Likewise,

during the lower-ing cycle, i. e., whenl articles vare being loweredfrom iioor y45 to-floorM, the

conveyorjwill startfto operate only after three conditions have beenfullled, i. e., firstly an article musthave been put intotheyruimerloading-position,Y thereby actuating lever SE counterclockwise tomove valve 1 2 to its dtt'ed vline position; secondly, the loading. door'Il must be lclosed, thereby operatingzlinkage 1S to move valve .lil :toits dotted line position; and thirdly, any article'in'the lower orlnormallyloading position fmust `hai/ ebeen removed so that pilot valvel2 is actuated by spring 82 to itsfull line position shown. in Fig. 2.On either the raising or lower 1ingcycle the presence of an article ateither terminal position may be simulated so farias opjeration' of thevcontrol apparatus is concerned' jby manually holding the appropriateone`of the hand levers iimtany against the tension,`

of the corresponding-spring 8 2 or 88.

Inorder to provide for-the automatic stopping Y of the hoist after thesame has moved the -distancebetween two consecutive'lights 35, controlmechanism comprising a shaft -S is drivenifrom `drive'shaft Slas bybevel gears 9i. .Shaft-90 is vshown (see Fig. l) driving a jcam 92through bevel'gears 93. Cam 92 has 'a circular periphery concentric withits'rotating axisand visprovided Witha single l depression or neutralpositionnotch 94-for-receiving-a; follower 95 cooperating with thelperiphery of this cam. Follower-95 is'carriedby the lower end of a link96 havingits-up per1end pivotallyfconne'cted to abell crank lever 91fulcrumedat 981v Lever B'lfis connectedv tosa frod V99Y having oneend-'portionextending-into valve casing 8 and fixed to the bypass valve9.

The other end portion of rod 99 is journalled in a fixed slide bearing|00.

A latch is pivoted at |02 on rod 99 and is normally held by gravity inthe position shown in Fig. 1. A suitable stop |03 on latch I0|, byengaging rod 99, prevents this latch from turning to a lower position. Acam |04 is driven from shaft 90 by suitable bevel gearing |05, so as toturn at the same rate as cam 92. Cam |04 has two angularly spaced rises|06 thereon adapted to engage a roller |01 carried by a lever |08fulcrumed at |09. A link IIO has its lower end pivotally connected tolever |08 and extends upwardly through a xed slide bearing block III,the upper end of this link carrying a roller ||2 for tripping the latchIOI. Thus, when either of the rises |06 passes under roller |01,depending on the direction of rotation, the bell crank lever |08 isactuated in a counter-clockwise direction to cause link I I0 to elevatelatch |0| so that the same cannot engage a roller I|6 carried by an armof a bell crank lever |I3 xed ona shaft I4. The other arm of bell cranklever I I3 has a depending link I I5 pivoted thereto, the lower portionof link I I5 extending through slide bearing block I I I and having aroller ||6 on its lower end for cooperating with the periphery of acircular cam II1. Cam |I1 is driven from shaft 90 by suitable bevelgearing to turn at the same rate as cams 92 and |04. The cams 92, |04,and |1 are so geared to the hoist driving mechanism that one revolutionof the cams takes place during the time required to move the conveyorchain 33 through the distance between adjacent flights 35.

The periphery of cam I I1 is concentric with its turning axis and has aperipheral depression IIB in which the roller II6 is illustrated in Fig.1 as engaged. A tension spring II9 extends between lever II3 and bearingblock for urging roller |I6 against the periphery of cam ||1. Shaft I|4has an upstanding lever |20 xed thereon, the upper end of which lever ispivotally connected to the outer end of the valve operating rod |2|connected to pilot control valve 58.

In order to provide for the manual operation of by-pass valve 9 asduring emergency starting or stopping of the hoist, a hand lever |22 isprovided in the lower loading position, i. e., at floor 44, the saidlever being fulcrumed at |23 and pivotally connected to rod 99. Suitablelinkage |24, or equivalent mechanical or electrical mechanism, may beused to connect lever |22 to a similar lever |25 at the upper position,i. e., at floor 45. A hand operated pump |26, shown adjacent lever |25,is employed for supplying pressure operating oil to the system in theevent motor I fails to operate due, for example, to the failure of thesupply current. When it is desired to operate pump |26, the manualoperating lever |21 of interlock valve I2 is thrown from the full lineposition of Fig. 1 to the dotted line position, thereby moving interlockvalve I2 to its dotted line position. The hand pump |26 may now beoperated to draw oil from pipe line I0 through valve casing Il and pipe|28 into the pump casing, whence the pump forces this oil through pipe|29 past check 30 into the supply pipe line 6. A similar hand operatedpump may be provided on floor 44, if desired. A pair of cooperatinginterlock contacts |3I are included in the control circuit for motor I,one of these contacts being carried by lever |21 and the other beingmounted on a xed support, the said contacts being engaged when theinterlock valve I2 is in its full line position shown in Fig. 1, andbeing disengaged when lever |21 is thrown to the right for manualoperation of the system by use of pump |26, thereby preventing thestarting of motor I during such manual operation.

In operation, assuming that it is desired to elevate articles from floor44 to floor 45, the control lever |21 is positioned in its full lineposition and operating lever 36 is positioned so that its detent 40engages the notch designated R" in segmental plate 4|, therebypositioning valves 22 and 69 in their full line positions. Motor I isnow started, thereby causing pump or A-end 5 to circulate oil throughpipe line 6, by-pass valve casing 8 and pipe line I0 back to the pump 5,as shown by the arrows in Figs. 1 and 2. At the same time, the drivenauxiliary pump A41 acts to deliver oil into the control pipe line 5I. Asmall portion of this oil enters branch pipe 56, and with the pilotcontrol valve 58 set in the full line position shown in Fig. 1, oilflows from pipe 56 through casing 51 and pipe 59 into the segmentalcasing 6|, thereby turning impeller 62 in a counter-clockwise directionuntil the same abuts stop screw 66, i. e., assuming that impeller 62 didnot initially abut this stop screw. This movement of impeller 62 causesoil to pass out of segmental casing 6| through pipe 60 into controlvalve casing 51 and thence this oil ows through pipe |32 to a returnpipe |33 leading back to reservoir 49. The pump 5 is thus caused todeliver oil at the minimum rate determined by the setting of screw 66.

Oil delivered from auxiliary pump 41 also Iiows through control pipeline 5| past valve 55` into the casing 68 of pilot reverse valve 69,from which casing this oil passes through pipe |34 to a pipe |35. Withinpipe |35 this oil flows to the casing 84 of pilot valve 12. Since thisvalve is in its full line position, the oil flows from casing 84 througha pipe |36 to a pipe |31, and thence into the casing 18 of pilot valve1|, which valve is in its full line position. From casing 18 the oilflows through pipe |38 back into the casing 84 of pilot valve 12, whencethis oil ows through pipe |39 into pipe |33 and thence back intoreservoir 49. A portion of the oil may iiowfrom pipe |38 back toreservoir 49 by way of pipe |40, valve casing 68 and pipe 54. Thecircuit of the oil from auxiliary pump 41 back to reservoir 49 is shownby arrows in Figs. 1 and 2.'

If now, an article 34 is loaded onto the hoist ight 35 at the lowerloading position, thereby depressing lever end portion 8| and actuatingpilot valve 1I to its dotted position, and the door 11 closed, therebyactuating pilot valve 10 to its dotted position, an oil control circuitis established to the hydraulic cylinder I5 for causing piston I6 tomove to the left so that the output of the pump or A-end 5 is connectedto the motor or B-end 24. This oil control circuit is Afrom pipe |34through pipe |35, pilot valve housing 18, pipe |31, valve housing 14 andpipe I8 to hydraulic cylinder I5, thereby forcing piston I6 toward theleft against the tension of spring I4 and actuating by-pass valve 9toward the left to its dotted line position, in which position oil fromsupply pipe line 6 ows through valve casing 8 and pipe line I9 to valvecasing 20 and thence through pipe 23 to the B-end 24 for operating themotor.

If either an article is not loaded on the hoist at the lower loadingstation or the door 11 is not closed, the hoist will not start, it beingnecessary that both an article be loaded on the hoist position, thepressure oil control circuit is prepared for supplying oil to hydrauliccylinder I to effect the starting of the conveyor or hoist. This circuitis from line 5| through reverse valve casing 68 to pipe |40, and frompipe I4!! through pipe |38, valve casing 84, pipe |36, pipe |31, valvecasing 14 and pipe IB to cylinder I5.

Piston I6 now actuates by-pass valve 9 to its dotted line position,thereby supplying pressure operating oil from supply pipe line 6,through valve casing 8, pipe I9, reverse valve casing 25, pipe 42 toB-end 24, and causing this motor to operate in the reverse directionfrom that previously described, so that conveyor sprockets 32 turnclockwise in Fig. 2, thereby lowering the articles from floor 45 towardoor 44, From the B-end the operating oil ows through pipe 23, casing 20,pipe 43, casing 8, pipe IU, casing and pipe I3 back to the A-end. Thehoist is accelerated, then operated at constant speed and thendecelerated by the mechanism controlled by cams 92, |04 and I I1 in thesame manner as previously described in connection with the operation ofthe hoist to elevate articles from floor 44 to floor 45.

The pilot valves 10, 1| and 12 likewise act in a manner similar to thatpreviously described to insure operation of the hoist only when anarticle is loaded at floor 45, one has been unloaded at oor 44 and door11 is closed.

Thus, it will be noted that in use, the operation of the hoist isentirely automatic and that as soon as an article is removed from thehoist delivery end and an article loaded in the hoist at the sending endand the hoist door 11. closed, the hoist moves as rapidly as practicablethrough the distance between consecutive flights 35 and then comes to astop. Owing to the use of hydraulic systems for both controlling andoperating the hoist, its operation is smooth, positive and takes placewithout noise, jarring, or undue stress on the operating parts.

When it is desired to empty the hoist of articles from floor 44, thehand lever 86a is held to the left after the last -article has beenloaded at oor 45. 'I'he hoist then operates in the manner previouslydescribed to lower the articles one flight for each article removed fromdoor 11. Likewise, when it is desired to empty the hoist from floor 45,the hand lever 80a is held to the right after the last article is loadedin door 11,

Check valve |30 in pipe I 29 leading from hand pump |26 preventspressure oil from pipe line 6 from backing up into the hand operatedpump |26 when the A-end is operating. Likewise check valve 1 in pipeline 6 prevents pressure oil from backing up into the A-end 5 whenthe'hand operated pump |26 is being used. In case the electric power tomotor should fail during the hoisting operation, the by-pass Valve 9will be held in hoisting position by the action of follower 95 riding oncam 92, and if the load on the conveyor is sucient, the gear reductionunit 28-30 and the B-end 24 may overhaul by rotating in the reversedirection until follower 95 re-enters neutral position notch 94. Link 96is preferably made of such shape that follower 95 cannot be forced outof neutral position notch 94 by the rotation of the conveyor, as when ittends to overhaul, so that this link 96 in eiTect locks the conveyor inplace.

It will be apparent that the conveyor 2| may pass between a plurality ofsuccessive oors or horizontallyY on one floor instead of between the twoshown, and that additional loading and unloading doors 11 may -be used,if desired, the

l2 said doors being connected to pilot valves arranged in series withpilot valve 1I) and pilot valve 12, respectively. Likewise while theinterlocking control system for the by-pass valve 9 has been shown ashydraulic, it will be understood that equivalent electric, or combinedelectric and fluid circuits may be utilized for this purpose.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is:

1. In combination, a fluid pressure hoist drive system and a hoistincluding an endless conveyor band operated thereby, said systemcomprising a rotary fluid pressure motor connected in driving relationto said hoist, pump means for supplying operating uid under pressure tosaid motor for operating the latter, and a fluid pressure control systemfor regulating the operating of said pump means and said motor, saidcontrol system operating in response to the imposition of a load on saidhoist to eiect the automatic operation of the latter through apredetermined cycle.

2. In combination, a iiuid pressure hoist drive system and a hoistoperated thereby, said system comprising a uid pressure motor connectedin driving relation to said hoist, main pump means for supplyingoperating fluid under pressure to said motor for operating the latter,and a fluid pressure control system for regulating the operating of saidpump means and said motor, said control system comprising a controlfluid circuit, auxiliary pump means for supplying control luid to saidcircuit, a hydraulic control for regulating the output of said main pumpmeans, and valve means in said control uid circuit and responsive to theloading of articles upon and the unloading of articles from said hoistfor controlling the operation of said hydraulic control, whereby theoutput vof said main pump means and hence the operation of said hoist iscontrolled in accordance with the demands on said hoist.

3. In combination, a uid pressure hoist drive system and a hoistoperated thereby, said system comprising a fluid motor for driving saidhoist, a pressure fluid operating circuit having variable pump means forcirculating pressure iiuid therein, valve means in said circuit forblocking the flow of fluid to said motor, and pilot valve meansresponsive to the loading and unloading of said hoist for causingactuation of said blocking valve means to elect the supply of pressurefluid from said pump means to said fluid motor for operating the latter.f

4. In combination, a uid pressure hoist drive system and a hoistoperated thereby, said system comprising a uid motor for driving saidhoist, a pressure uid operating circuit having variable pump means forcirculating pressure fluid therein, a fluid pressure operated controlmeans for regulating the output of said variable pump means, valve meansin said circuit for by-passing the output of said pump means, pilotvalve means responsive to the loading and unloading of said hoist forcausing actuation of said bypass valve means to eiect the supply ofpressure fluid from said pump means to said fluid motor for operatingthe latter, and control valve means responsive to the actuation of saidby-pass valve means and to the operation of said hoist for regulatingthe supplyof pressure fluidto said4 variable pump control means. f v- 5.In combination, av uidpressure hoist driveV system and a hoist operated.thereby, said system comprising a iluid motor for driving; said hoist, apressure uid operating circuit having variable pump means forcirculating pressure iiuidtherein, a fluid pressure operated controlmeans forY regulating the output of said variable pump means, valvemeans in said circuit for by-passing the output of said pump means,pilot valve means responsive to the loading and unloading of said hoistfor causing actuation of said by-pass valve means to effect the supplyof pressure fluid from said pump means to said uid motor for operatingthe latter, reversing valve means interposed between said by-pass valvemeans and said fluid motor for reversing the direction of operation ofthe latter to effect reverse operation of said hoist, and control valvemeans responsive to the actuation of said by-pass valve means and to theoperation of said hoist for regulating the supply of pressure actuatingfluid to said variable pump control means.

6. In combination, a uid pressure hoist drive system and a hoistoperated thereby, said system comprising a iiuid motor for driving saidhoist, a pressure uid operating circuit having pump means forcirculating pressure uid therein, valve means in said circuit forby-passing the output of said pump means, fluid pressure cylinder andpiston means for actuating said by-pass valve means to establish thesupply of pressure fluid from said pump means to said fluid motor foroperating the latter, and pilot valve means responsive to the loading ofsaid hoist for controlling the supply of operating uid to said uidpressure cylinder and piston means.

7. In combination, a uid pressure hoist drive system and a hoistoperated thereby, said system comprising a variable speed uid motor fordriving said hoist, a pressure fluid operating circuit having variableoutput pump means therein for circulating pressure fluid therein, aby-pass valve in said circuit, said valve being biased for bypassing theoutput of said pump means, fluid pressure cylinder and piston means foractuating said by-pass valve to enable the supply of pressure fluid fromsaid pump means to said fluid motor for operating the latter, pilotvalve means responsive to the loading and unloading of said hoist forcontrolling the supply of operating fluid to said fluid pressurecylinder and piston means, and means responsive to the actuation of saidby-pass valve means and to the operation of said hoist for regulatingthe output of said variable pump means, whereby the speed of said hoistis controlled.

8. In a iiuid pressure hoist drive system for operating hoists, a uidpressure pump having a variable output, a fluid pressure hoist motorsupplied from said pump, a uid pressure operated control device forregulating the output of said pump, and valve means controlled inresponse to the loading and unloading of the hoist and to the operationof the same for determining the supply of operating fluid to saidcontrol device.

9. In a fluid pressure hoist drive system for operating hoists, a fluidpressure pump having an adjustable control shaft for varying the outputof said pump, a fluid pressure hoist motor supplied from said pump, afluid pressure control device having an impeller connected to saidcontrol shaft for varying the adjustment thereof, adjustable stop meansfor limiting the movement 14 of seid. muelles. legalis for Supplying.-@gaat Pressure-Hwa aedvaflvemsansrs; "remates loading. and unloading Qf;the heist ad t0., the'. Operation. 0f, the; fOr-,Centraline the; HQ'W:of-pressure fluidvfroqm said supplying mean to said control device,thereby-determinmgfthe-adiustment if-'Seid Castrol. Shaft. 10. n a fluidpressureA hoistY e drive Srsisgr f9.2' Operating hasta a fluidpresvrenumpih' iria@- Variable. output, a fluid pressure heist 1119.150?s, plied from. purpurea-a guientes-ure @Html des Vice; far regulatingthe output ofV Said. rum-a; a valve connected to said control device andcontrolled in response to the loading and unloading of the hoist and tothe operation of the same for determining the supply of operating uid tosaid control device, and adjustable choke means included in theconnection between said valve and said control device for determiningthe speed of operation of said device and hence the rate of change ofsaid pump output.

l1. In combination, a fluid pressure hoist drive system and a hoistoperated thereby, said system comprising a fluid pressure motorconnected in driving relation to said hoist, pump means for supplyingoperating iluid under pressure to said motor for operating the latter,and a fluid pressure control system for regulating the operating of saidpump means and said motor, said control system comprising a controlfluid circuit, a hydraulic control for regulating the output of saidpump means, and valve means in said control uid circuit and responsiveto the loading of articles upon and the unloading of articles from saidhoist for controlling the operation of said hydraulic control, wherebythe output of said pump means and hence the operation of said hoist iscontrolled in accordance with the demands on said hoist.

12. In combination, a fluid pressure hoist drive system and a hoistincluding an endless conveyor band operated thereby, said systemcomprising a rotary fluid pressure motor connected in drivingv relationto said hoist, pump means for supplying operating uid under pressure tosaid motor for operating the latter, and a liuid pressure control systemfor regulating the operating of said motor, said control systemcomprising a control fluid circuit, a hydraulic control for regulatingthe fluid supply to said motor, and valve means in said control fluidcircuit and responsiveV to the loading of articles upon said hoist forcontrolling the operation of said hydraulic Control, whereby theoperation of said hoist is controlled in accordance with the demands onsaid hoist.

13. In combination, a fluid pressure hoist drive system and a hoistoperated thereby, said system comprising a fluid motor for driving saidhoist,

a pressurer fluid operating circuit having pump means for circulatingpressure uid therein, valve means in said circuit for blocking the ilowof fluid to said motor, a fluid motor for operating the blocking valvemeans, and pilot valve means responsive to the loading of said hoist forcausing actuation of said blocking valve means to effect the supply ofpressure fluid from said pump means to said uid motor for operating thelatter.

14. A conveyor system for transferring articles from a loadingstationtol an unloading station comprising in combination an endlessband conveyor having a plurality of flights secured thereto and spacedso as to carry a plurality of articles in spaced relation along oneportion of the band lying between the stations, driving means 15connected to operate the conveyor band, and a control system for thedriving means including starting means responsive conjointly to theloading of an article on the conveyor at the loading station and theunloading of an article from the conveyor at the unloading station toautomatically start the driving means, said loading station having abarrier shiftable between an open position permitting free access to theconveyor band and a closed position in which accidental removal ofarticles from loaded position is prevented, said starting means having aconnection with said barrier effective to prevent starting when thebarrier is open, and stopping means responsive to travel of the conveyorthrough the distance between adjacent flights to automatically stop thedriving means independently of the starting means, whereby when theconveyor is once lled with articleslbetween the stations, delivery ismade automatically by a single advancing movement of the conveyor anddirectly responsive to the loading and unloading of articles on and offthe conveyor.

ARTHUR L. ELLIS.

